| 1. |
- Järvinen, Topias, et al.
(författare)
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An energy harvester based on UV-polymerized short-alkyl-chain-modified [DBU][TFSI] ionic liquid electrets
- 2024
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 12:3, s. 1746-1752
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Tidskriftsartikel (refereegranskat)abstract
- Three short-alkyl-chain-modified [DBU][TFSI] ionic liquids (ILs) were synthesized and utilized in electrets. The electrets were prepared by mixing a UV-curable polymer with the ionic liquids followed by polymerization while applying an external electric field, thus forming spatially separated anions and cations in the proximity of opposing surfaces of the composite slabs. The immobilized surplus surface charge was measured by periodically engaging the electret with a metal counter electrode plate and detecting the displacement current using a charge amplifier. The results show that electrets based on polymerized [DBU][TFSI] ILs have a separated surface charge density of up to 64 nC × cm−2, which equals an energy harvesting density of 7.0 nJ × cm−2. Control measurements repeated after a few days to assess the stability and reproducibility of the systems showed that while charge separation reverses over time to some extent, the polymerized ionic liquid samples are resilient to exposure to atmospheric conditions and could be utilized in this type of energy harvesting scheme.
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| 2. |
- Mendes, Pedro S. F., et al.
(författare)
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Conference Report: YEuCat Better Together - Collaborative Catalysis in a Changing World
- 2022
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Ingår i: ChemCatChem. - : Wiley. - 1867-3899 .- 1867-3880. ; 14:15
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- "YEuCat Better Together was the first collaborative event organized by the Young European Catalysis Network with the goal of joining young minds to propose an innovative catalytic solution to a global problem." This and more about YEuCat Better Together can be found in this Guest Editorial.+
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| 3. |
- Nuri, Ayat, et al.
(författare)
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Pd Nanoparticles Stabilized on the Cross-Linked Melamine-Based SBA-15 as a Catalyst for the Mizoroki–Heck Reaction
- 2022
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Ingår i: Catalysis Letters. - : Springer. - 1011-372X .- 1572-879X. ; 152, s. 991-1002
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses. Graphic Abstract: [Figure not available: see fulltext.]
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| 4. |
- Nuri, Ayat, et al.
(författare)
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Pd Supported IRMOF-3 : Heterogeneous, Efficient and Reusable Catalyst for Heck Reaction
- 2019
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Ingår i: Catalysis Letters. - : Springer. - 1011-372X .- 1572-879X. ; 149:7, s. 1941-1951
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Tidskriftsartikel (refereegranskat)abstract
- IRMOF-3 with a high surface area prepared by a hydrothermal method was used for deposition of Pd(OAc)(2) on IRMOF-3 particles. The final catalyst was characterized with FT-IR, nitrogen physisorption, thermogravimetry, scanning electron microscopy, transmission electron microscopy combined with energy dispersive X-ray analysis, wide angle X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy. The prepared porous catalyst was effectively used in the Heck coupling reaction in the presence of an organic base. The reaction parameters such as the type of base, amounts of catalyst and solvents, temperature were optimized. The catalyst was then easily separated, washed, and reused 4 times without significant losses of catalytic activity. [GRAPHICS] .
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| 5. |
- Nuri, Ayat, et al.
(författare)
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Synthesis and Characterization of Palladium Supported Amino Functionalized Magnetic-MOF-MIL-101 as an Efficient and Recoverable Catalyst for Mizoroki–Heck Cross-Coupling
- 2020
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Ingår i: Catalysis Letters. - : Springer. - 1011-372X .- 1572-879X. ; 150:9, s. 2617-2629
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic particles were prepared by a hydrothermal method and then successively covered by Metal–Organic-Frameworks MIL-101-NH2 with a high surface area. This was followed by deposition of Pd(OAc)2 on Fe3O4–NH2@MIL-101-NH2 particles. The final catalyst was characterized with FT-IR, nitrogen physisorption, thermogravimetry (TGA), scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), wide-angle X-ray diffraction spectroscopy (XRD) and X-ray photoelectron spectroscopy (XPS). The prepared magnetic catalyst was effectively used in the Heck coupling reaction in the presence of an inorganic base. The reaction parameters such as the base type, amounts of catalyst and solvents, temperature, and substrates ratios were optimized. The catalyst was then magnetically separated, washed, and reused 7 times without losing significantly catalytic activity.
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| 6. |
- Pitkänen, Olli, et al.
(författare)
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Evaluation of short alkyl chain modified [DBU][TFSI] based ionic liquids as supercapacitor electrolytes
- 2024
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 475
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Tidskriftsartikel (refereegranskat)abstract
- The need of new electrolytes with wide electrochemical window, good stability and conductivity has promoted novel ionic liquids (ILs) as new solutions for supercapacitors. In this work, four hydrophobic room temperature ionic liquids based on organic superbase-derived cations and Trifluoromethanesulfonimide (TFSI) anion were synthetized. The structures of the novel ILs were analyzed, characterized and their performance as a supercapacitor electrolyte was evaluated. The ILs have high decomposition temperatures of up to 490 °C and electrochemical window up to 4.8 V. It was found that there was an optimal chemical structure providing the best stability and operational potential window coupled with moderate conductivity. The IL with the shortest alkyl chain structure provided the highest conductivity but suffered from instability. The performance of the ILs with longer alkyl chains was hindered by lower conductivities and, in the case of the largest chemical structures, also by reduced cyclic stabilities in open air. However, the ionic liquid with moderate alkyl chain length was found to be stable even in open air providing decent conductivity, which can be utilized in future research to develop other hydrophobic ionic liquids suitable as supercapacitor electrolytes.
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| 7. |
- Vucetic, Nemanja, et al.
(författare)
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Competing commercial catalysts: Unprecedented catalyst activity and stability of Mizoroki-Heck reaction in a continuous packed bed reactor
- 2022
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 433
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Tidskriftsartikel (refereegranskat)abstract
- Main obstacle for adopting continuous processes as a standard technology for Mizoroki-Heck reaction usually lies in its specific reaction mechanism. Here we present an important step forward answering the challenges unraveled through a comprehensive study that provides deeper understanding on the Mizoroki-Heck reaction, in particular the case when iodobenzene and butyl acrylate react in a continuous packed bed reactor in the presence of a Pd Supported Ionic Liquid Catalyst (SILCA). On-line UV–VIS spectrometry supported by ICP-OES, TEM and XPS measurements were carried out and the catalyst leaching was minimized. Finally, simple continuous flow process was proposed resulting in a high catalytic activity (up to 1470 molArI molPd−1h−1) and reaching productivity in the range of 12,000 to 16,000 molArI molPd−1 thus competing with the performance of commercial catalysts.
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| 8. |
- Vucetic, Nemanja, et al.
(författare)
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Preparation and characterization of a new bis-layered supported ionic liquid catalyst (SILCA) with an unprecedented activity in the Heck reaction
- 2019
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Ingår i: Journal of Catalysis. - : Elsevier. - 0021-9517 .- 1090-2694. ; 371, s. 35-46
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Tidskriftsartikel (refereegranskat)abstract
- A new bis-layered supported ionic liquid catalyst (SILCA) loaded with palladium was designed and successfully applied for the Heck reaction of iodobenzene and methyl acrylate. The silica modified catalyst consisting of the first ionic liquid layer - covalently anchored imidazolium bromide - on which the second layer, made of pyridine-carboxylic acid balanced with tetramethylguanidinium cation was attached, resulted in a catalyst with high activity. High turnover frequencies of 22,000 h(-1) were achieved in reactions with a low palladium loading as 0.009 mol %. Lower TOFs, indicating on palladium dimerization was detected when higher amounts were used. The TMG cation had a purpose to recapture and stabilize the Pd nanoparticles thus followed a release and catch mechanism. In order to get a full understanding of the catalyst structure and behaviour, the catalyst was characterized by means of nitrogen physisorption, thermal gravimetric analysis, infrared spectroscopy, scanning electron and transmission electron microscopes, solid-state NMR, X-ray photoelectron spectroscopy and inductively coupled plasma spectroscopy. The catalyst preserved good activity in five cycles.
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| 9. |
- Vucetic, Nemanja, et al.
(författare)
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Tuned Bis-Layered Supported Ionic Liquid Catalyst (SILCA) for Competitive Activity in the Heck Reaction of Iodobenzene and Butyl Acrylate
- 2020
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Ingår i: Catalysts. - : MDPI. - 2073-4344. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- A thorough experimental optimization of supported ionic liquid catalyst (SILCA) was performed in order to obtain a stable and efficient catalyst for the Heck reaction. Out of fifteen proposed structures, propyl imidazolium bromide-tetramethylguanidinium pentanoate modified SiO2 loaded with PdCl2 appeared to be the most stable and to have a good activity in the reaction between butylacrylate and iodobezene, resulting in a complete conversion in 40 min at 100 °C, in four consecutive experiments. This study elucidated on the stability of the catalytic system with an ionic liquid layer during the catalyst synthesis but also under reaction conditions. In the bis-layered catalyst, the imidazolium moiety as a part of internal layer, brought rigidity to the structure, while in external layer pentanoic acid gave sufficiently acidic carboxylic group capable to coordinate 1,1,3,3-tetramethylguanidine (TMG) and thus, allow good dispersion of Pd nanoparticles. The catalyst was characterized by means of XPS, FT-IR, TEM, ICP-OES, ζ-potential, EDX, TGA, and 13C NMR. The release and catch mechanism was observed, whereas Pd re-deposition can be hindered by catalyst poisoning and eventual loss of palladium.
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